Dimethyl methylphosphonate → HCID 11119485, compound

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Reaction Steps

To a solution of 5 g. of dimethyl methylphosphonate in 100 ml. of dry tetrahydrofuran cooled to about -78° under nitrogen, there is added with stirring one equivalent of n-butyl lithium in hexane. After about 10 minutes, there is added one molar equivalent of 3-methoxy-16-oxaestra-1,3,5(10), 8,14-pentaen-17-one in dry tetrahydrofuran while maintaining the temperature at about -78°. The mixture is allowed to warm to room temperature and then left to stand at room temperature for 5 hours. The mixture is diluted with water and then extracted with ether. The ether extracts are combined and concentrated to furnish a residue which is chromatographed on neutral alumina eluting with benzene to afford 3-methoxy-14β-estra- 1,3,5(10),8,15 -pentaen-17-one and 3-methoxy-14α-estra-1,3,5(10),8,15-pentaen-17-one which can be further purified by recrystallization from aqueous methanol.

Provenance & Evidence